Omaopio Water Tank Replacement

The project consisted of replacement of the existing 500 hundred-thousand-gallon metal tank with a two (2) million-gallon water concrete tank, a new concrete driveway and access road. The new prestressed concrete tank reduces future maintenance expenses and provides the best value tank over the 100+ year design life. The tank’s concrete core-wall was prestressed in both the vertical and circumferential directions which placed the walls in permanent compression, thereby utilizing concrete and steel most efficiently. The anchored flexible base design of the tank incorporated 98 specialized seismic connection anchors at the floor to wall connection to maximize the ductility of the structure.

The tank is sited approximately 30% up the volcano’s slope with the tank’s high-water elevation at 3948.5’. The steep construction access road, with a maximum grade of 24%, required significant coordination between the Owner, contractor and material suppliers and required concrete truck loads to be limited to short loads to ensure access and material quality were maintained.

Kula, HI
Department of Water Supply
Sato and Associates